Goals and Symptoms

Which values will be measured by autotuning at ATV31? Is it only the RSC or will other values be measured too? If other values will be measured, which values is it and have these values a logical address (read/writable)?

Facts and Changes

ATV31, autotuning

Causes and Fixes

The autotuning measures the motor stator resistance (RSC) at nominal current without the motor running in order to set the automatic stator voltage drop compensation (IR).
Rsc = Phase-to-phase resistance/2 (initial measurement, 1st Tun after Rsc=Init).
This value can be modified if the value measured by the autotuning operation is incorrect (Tun with long cable length, output filter etc).
Caution: The effect on the motor behaviour of modifying Rsc is dependent on Ufr, whose action is not linear.
There are no other measurement with the autotuning.
For the motor it's depending of the motor data :
- UNS = determine the parameters used in motor control. Adjustment of the voltage frequency ratio nominal point and motor model internal parameters: reference flux, main inductance (Ls).
- FRS = determine the parameters used in motor control for adjustment of the voltage frequency ratio nominal point and nominal ramp time during acceleration and deceleration.
- NSP = determine the parameters used in motor control for rotor time constant (Tr), calculating the stator frequency applied to the machine and calculation of the slipping (SLP 100% = synchronism speed - NSP).
- COS = Adjusting the machine no-load current (Io) Cos= SQR(1-(Io²/In²)) and calculating the stator frequency applied to the machine.